JPS61296783A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To enable the change of the intensity of light of the title laser device by a method wherein two kinds of regions having different forbidden band width or the thickness of a quantum well layer are formed, thereby enabling to emit the light spot having two different wavelength with the controlled lateral mode of oscillation. CONSTITUTION:First, an active layer 3 of quantum well structure, an n-GaAlAs clad layer 4, and an n-GaAs layer are successively formed on an n-GaAs substrate 1 using an organic metal thermal decomposition vapor-phase growing method (MOCVD method). Then, a p-GaAs cap layer 6 and a Zn diffusion region 7 are formed by diffusion Zn on the n-GaAs layer and the clad layer 2 by performing a selective diffusion method. Subsequently, an n-electrode 8 is formed using a vapor-deposition method, and after an n-electrode is formed on the whole surface on the cap side, a stripe-like n-electrode 10 is formed by performing an etching. A p-electrode is formed on both sides of the electrode 10 using a vapor-deposition method and a lift-of method. Lastly, a groove 11 is provided by applying an etching to the p-electrode and the GaAs layer located on both sides of the n-electrode, and electrodes 9 and 10 are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a semiconductor laser that emits light at two different wavelengths with controlled transverse modes, and particularly to a semiconductor laser that can independently change the intensity of the two light emissions. Regarding.

[Background of the invention]

A single semiconductor laser that emits light from two or more main light spots with different emission wavelengths is a laser that emits light at two or more main light spots with different emission wavelengths.

March 15, 1980 Section 441 (W-T-Tsan
g”” CW +multivalength t
ranseverse-junction-strip
e 1asers grown by molecule
ar beamapitaxy operating
predominantly in 'sin
gle-1ongitudinal modes”A
ppl Phys 1ett.

Vo136 C6), 15March1980. P
, 441). However, since the light intensity of each light spot cannot be changed independently, its use is inevitably limited.

[Purpose of the invention]

An object of the present invention is to provide a semiconductor laser structure that emits light spots of two different wavelengths in which the transverse mode of oscillation is controlled and can vary the light intensity of each spot.

[Keystone of the invention]

The oscillation wavelength of a semiconductor laser is determined by the forbidden band width of the active layer in a normal double hetero type laser, and in the case of a quantum well type laser, it also depends on the thickness of the well layer in addition to the forbidden band width.
(see figure). Therefore, in order to obtain a semiconductor laser that emits light at two wavelengths, it is necessary to form two types of regions with different forbidden band widths or quantum well layer thicknesses.

An example of the configuration of the present invention is shown in FIG. 1, and will be explained using this. FIG. 3 shows an enlarged view of the active layer 3 in FIG. 1. As shown in FIG. The forbidden band width and/or the thickness of the quantum well layer are different from B. Since a barrier layer is provided between active regions A and B, active region A emits light when electricity is applied between electrodes 9 and 10 shown in FIG. 2, and becomes active when electricity is applied between electrodes 8 and 9. The area glows. At this time, by varying the applied current, the light emission intensities of active regions A and B can be varied independently.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 This will be explained using FIGS. 1 and 3.

An example of a method for manufacturing a semiconductor laser of the present invention will be described with reference to FIG.

First, n -GaA is deposited on the n -GaAs substrate 1.
Q As cladding layer 2, quantum well structure active layer 3, n
-G sA Q As cladding layer 4 and n-GaAs layer are sequentially formed using a metal organic pyrolysis vapor deposition method (MOCVD method). Next, Zn was converted into n-G by selective diffusion method.
The p-GaAs cap layer 6 and Zn diffusion region 7 are formed by diffusing from the aAs layer to the cladding layer 2. Subsequently, an n-electrode 8 is formed using a vapor deposition method, and an n-electrode is also formed on the entire surface of the cap side, and then a striped n-electrode 10 is formed by etching. Then, p electrodes are formed on both sides of the electrode 10 using a vapor deposition method and a lift-off method, and finally p electrodes on both sides of the n electrode and Ga
The As layer cap layer is etched to provide grooves 11 to form electrodes 9 and 10.

In this embodiment, as shown in FIG. 3, the active layer has a quantum well structure. That is, the thickness of each layer is
In active region A, the well layer is 3 nm thick and the barrier layer is 4 nm thick.
m, and in active region B, the well layer is 6 nm thick, the barrier layer is 4 nm thick, and Ga between active regions A and B is...
The thickness of the A Qa, 4sA s barrier layer was 8 nm.

Example 2 This will be explained using FIGS. 4 and 5.

FIG. 4 shows the manufacturing process of the semiconductor laser of this embodiment.

First, on an n-GaAs substrate 1, an n-GaAsAs cladding layer 2, an active layer 3 having a quantum well structure, and an n"Ga
Molecular beam epitaxy (MBE) for AsAs cladding layer 4
(FIG. 4(a)). Next, Zn ions are selectively implanted (Fig. 4(b)), and n
- Form a GaAQAs cladding layer 4 (FIG. 4(C)). Next, Zn ion implantation was performed again (Fig. 4 (
d) ), forming the n-GaAQAs cladding layer 4' and the n-GaA3 cap layer 5 (
Figure 4(e)). Next, Zn ions are selectively implanted again to form a part of the n-GaAs into a p-GaAs cap layer 6'. Finally, electrodes 8.9 and 10 are formed in the same manner as in Example 1.

Example 3 This will be explained using FIG.

Although the structure is the same as that shown in FIG. 1, the structure of the active M3 and the cladding layers 2 and 4 in the vicinity of the active layer 3 is shown in FIG. That is, the active layer has a 6 nm thick Gaa layer between a 3 nm thick quantum well layer and a 6 nm thick quantum well layer.
The structure includes ssA Qa and 4sA s barrier layers, and the A Q As mixed crystal ratio of the cladding layer becomes smaller as it approaches the active layer. This change in the A Q A s mixed crystal ratio causes the refractive index distribution n (r) of the cladding layer to be expressed by the following equation.

(However, O < r < t) n (r) = n, (r:> t) Here, 7 t (n x - n *) ' / nt,
nl is the refractive index (approximately 3.452) when the A n A s mixed crystal ratio X is 0.20, and n2 is the refractive index when the A Q A s mixed crystal ratio X is 0.
．． 45 (approximately 3.289). Further, r is a coordinate in the cladding side direction with the origin being the boundary between the wall of the quantum well layer and the cladding layer. Also, t is AuAs
This is the thickness of the cladding layer region where the mixed crystal ratio is changing. α, which determines the slope, was set to 5.

The semiconductor lasers of Examples 1, 2 and 3 above are as follows.

When a forward bias was applied between electrodes 9 and 10, a laser beam with a wavelength of 0.78 μm was emitted, and when a forward bias was applied between electrodes 8 and 9, a laser beam with a wavelength of 0.83 μm was emitted. Furthermore, it was possible to adjust the intensity of each emitted light by controlling the bias current. The threshold current value was 50 to 80 mA, and the horizontal mode was single until the emitted light output was 30 mW.

In the above explanation, GaAQAs-based material was used, but InGaAsP-based InGa
It goes without saying that similar results can be obtained even if a P-based compound semiconductor material or the like is used.

In addition, the thickness of the quantum well layer is 2 to λ Onm, the thickness of the barrier layer is 2 to 10 nm, and there is a problem that the two active regions are narrowed.
The thickness of the wall layer was within the range of 2 to 10 [theta]nm in order to implement the present invention.

〔Effect of the invention〕

According to the present invention, a semiconductor has two active regions that emit laser light of different wavelengths, the amount of carrier injection into each region can be independently controlled, and the amount of emitted light of the two can be independently varied. This has the effect of allowing new and advanced optical application devices to be developed.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the outline and embodiments of the present invention, Fig. 2 is a diagram used for detailed explanation of the present invention, Fig. 3 is a diagram used for explaining Embodiment 1, and Figs. 4 and 5. 6 is a diagram used to explain the second embodiment, and FIG. 6 is a diagram used to explain the third embodiment. 1...Substrate, 2,4.4'...Clad layer, 5,6
゜6'...Cap layer, 3...Active layer, 7...Z
Diffusion layer, 7'...Zn ion implantation layer, 8, 9 and 10...31 Surplus talent t 5 Inadequacy 6 Figure χ;ρ /, 2 /, 45 Basic side

Claims (1)

[Claims] 1. In a semiconductor laser having an active layer including two active regions with a narrow barrier, the forbidden band width or thickness of the semiconductor layer constituting the active region, or the forbidden band width and thickness 1. A semiconductor laser device characterized in that it has two pairs of electrodes having different characteristics, so that the two active regions can be controlled independently. 2. The semiconductor laser device according to claim 1, wherein the active region has a current confinement structure.